Momentum

From: Subject: Momentum Date: Wed, 29 Dec 2004 06:49:16 -0500 MIME-Version: 1.0 Content-Type: multipart/related; type="text/html"; boundary="----=_NextPart_000_0121_01C4ED72.8396A880" X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0121_01C4ED72.8396A880 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Location: http://prkw.com/pmcmom.html Momentum

Multiple Choice Test
Indicate the correct answer by=20 clicking on the button next to the numbers 1, 2, 3 or 4. There = is only=20 one correct answer per question. After you have answered=20 all multiple choice questions compare your choices = with=20 the correct answers.

Momentum

1.) A cricket ball of mass 'm' travelling = at a speed=20 of 'v', is struck back in the opposite direction with the same speed = 'v'. The=20 magnitude of the change in momentum of the ball is=85

1 2 mv

2 mv²

3 mv

4 0

2.) A moving object X has a mass = m and=20 speed v. Another moving object Y will have twice the momentum of = X if it=20 has a mass and velocity of:

mass velocity

1 1/2 m 1/2 v

2 1/2 m 2 v

3 4 m 1/2 v

4 4 m 2 = v
x mass =3D 2mv? Only in 3 = we get 2mv after multiplication.")' type=3Dbutton value=3DExplanation>

3.) A soccer ball of mass 1 kg = strikes a=20 wall at right angles with a velocity of 2 m/s as shown in the = sketch. It=20 bounces back with a velocity of 1,5 m/s.
The impulse of the = wall on=20 the ball (in kg.m/s) is ...=20

1 0,5 to the right

2 0,5 to the left

3 3,5 to the right

4 3,5 to the left

4.) Two trolleys A and B are moving towards = another as=20 shown in the diagram at the right. They collide and come to rest = at the=20 point of impact. From this observation we can conclude that the = trolleys=20 have =85

1 equal masses.

2 were moving with equal and opposite = momentum.

3 were moving with equal and opposite = velocities.

4 were moving with equal kinetic=20 energies.
2 it is not the case.")' type=3Dbutton value=3DExplanation>

5.) A snooker ball A moves at a velocity of 6 = m/s and=20 collides with two identical snooker balls B and C, as shown in = the=20 sketch. Ignore all friction.
After the collision =85 =

1 balls A and B are stationary and C moves at 6 = m/s.

2 balls A and B are stationary and C moves at 3 = m/s.

3 ball A is stationary and B and C move at 3 = m/s.

4 all three balls move at 2 = m/s.

6.) The diagram at the right shows two blocks = A and B,=20 which are connected by a rubber band. The mass of A is twice the = mass of=20 B.
The two blocks are pulled apart on a smooth horizontal = surface=20 and released simultaneously. When they are released, the blocks = collide=20 and =85

1 both move to the right.

2 both move to the left.

3 both remain at rest.

4 block A remains at rest and B moves to the=20 right.

7.) Newton's second law of motion states:

1 For every action there is an equal and opposite=20 reaction.

2 A body will remain at rest unless acted upon by an = unbalanced=20 force.

3 The force acting on a body equals the rate of change of=20 momentum.

4 A body will move with uniform motion in a straight line, = unless=20 acted upon by an unbalanced = force.

8.) Two vehicles move towards each other on a = frictionless=20 road as shown in the sketch below. The two cars collide and = immediately come=20 to a standstill.

During the collision, the total momentum of = the two=20 vehicles will =85

1 decrease.

2 stay constant.

3 firstly increase and then decrease.

4 firstly decrease and then = increase.

9.) An open truck is moving horizontally with a = constant=20 velocity along a frictionless track underneath a grain bin. Grain, = falling=20 vertically down, now starts falling into the truck, partly filling it = as it=20 moves along. What will happen to the momentum of the truck = accumulating grain?=20

1 It will decrease.

2 It will increase.

3 It will first increase and then decrease.

4 It will stay the = same.

10.) Two trolleys, X and Y, of masses 4 kg and 6 = kg=20 respectively, are held stationary on a horizontal surface with a = spring=20 compressed between them. Two barriers are situated equidistant from = each=20 trolley as shown in the diagram below.

When the spring is released =85

1 trolley X will strike the barriers first.

2 trolley Y will strike the barrier first.

3 both trolleys will strike the barrier at the same=20 time.

4 the final momentum is zero and therefore the trolleys = will not=20 reach the barrier.

Results

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	mass	velocity
1	1/2 m	1/2 v
2	1/2 m	2 v
3	4 m	1/2 v
4	4 m	2 = v

1	equal masses.
2	were moving with equal and opposite = momentum.
3	were moving with equal and opposite = velocities.
4	were moving with equal kinetic=20 energies.

1	balls A and B are stationary and C moves at 6 = m/s.
2	balls A and B are stationary and C moves at 3 = m/s.
3	ball A is stationary and B and C move at 3 = m/s.
4	all three balls move at 2 = m/s.

1	both move to the right.
2	both move to the left.
3	both remain at rest.
4	block A remains at rest and B moves to the=20 right.

1	For every action there is an equal and opposite=20 reaction.
2	A body will remain at rest unless acted upon by an = unbalanced=20 force.
3	The force acting on a body equals the rate of change of=20 momentum.
4	A body will move with uniform motion in a straight line, = unless=20 acted upon by an unbalanced = force.

1	decrease.
2	stay constant.
3	firstly increase and then decrease.
4	firstly decrease and then = increase.

1	It will decrease.
2	It will increase.
3	It will first increase and then decrease.
4	It will stay the = same.

1	trolley X will strike the barriers first.
2	trolley Y will strike the barrier first.
3	both trolleys will strike the barrier at the same=20 time.
4	the final momentum is zero and therefore the trolleys = will not=20 reach the barrier.